From everything I've read, it is best to use the media type tag names. So,
if you have an audio file you are to play, use the <audio> tag. (This is
what I remember reading off of both RealMedia and W3C's web sites). The only
reason you'd use <ref> is because you are not sure what media type will be
used, or for generic reasons.
Since "RealPix" is a RealMedia format, I would go with what they are saying
to use. There is no defined use by the W3C, to my knowledge, about RealPix.
But if you use the <ref> tag, there should be no problem either, since the
rules of SMIL say that <ref> can be used by any of the media formats. If a
SMIL viewer can not read the RealPix format, then they will not display it
(possibly giving an error message).
Another time you may want to use the <ref> tag is for audio that is in video
format (eg. QuickTime *.mov audio files).
Hope this helps
-----Original Message-----
From: TAKESATO HAYASHI [mailto:take@takesato.com]
<snip>
I type SMIL following.
<par endsync="first">
<ref src="tabioto02.rp" region="RealPix"/>
<textstream src="tabioto02.rt" region="RealText"/>
<audio src="tabioto02.rm"/>
</par>
I checked my SMIL tag use RealNetworks SMIL Evaluator.
( http://www.real.com/devzone/library/creating/smileval/ )
It suggested me, its better to use "img" for RealPix.
Which is better "ref" and "img" for RealPix?
(better: I mean right in W3C SMIL RFC)
<snip>